/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.buffer;

import io.netty.util.IllegalReferenceCountException;
import io.netty.util.internal.StringUtil;

/**
 * Default implementation of a {@link ByteBufHolder} that holds it's data in a {@link ByteBuf}.
 */
public class DefaultByteBufHolder implements ByteBufHolder {

  private final ByteBuf data;

  public DefaultByteBufHolder(ByteBuf data) {
    if (data == null) {
      throw new NullPointerException("data");
    }
    this.data = data;
  }

  @Override
  public ByteBuf content() {
    if (data.refCnt() <= 0) {
      throw new IllegalReferenceCountException(data.refCnt());
    }
    return data;
  }

  /**
   * {@inheritDoc}
   * <p>
   * This method calls {@code replace(content().copy())} by default.
   */
  @Override
  public ByteBufHolder copy() {
    return replace(data.copy());
  }

  /**
   * {@inheritDoc}
   * <p>
   * This method calls {@code replace(content().duplicate())} by default.
   */
  @Override
  public ByteBufHolder duplicate() {
    return replace(data.duplicate());
  }

  /**
   * {@inheritDoc}
   * <p>
   * This method calls {@code replace(content().retainedDuplicate())} by default.
   */
  @Override
  public ByteBufHolder retainedDuplicate() {
    return replace(data.retainedDuplicate());
  }

  /**
   * {@inheritDoc}
   * <p>
   * Override this method to return a new instance of this object whose content is set to the
   * specified {@code content}. The default implementation of {@link #copy()}, {@link #duplicate()}
   * and {@link #retainedDuplicate()} invokes this method to create a copy.
   */
  @Override
  public ByteBufHolder replace(ByteBuf content) {
    return new DefaultByteBufHolder(content);
  }

  @Override
  public int refCnt() {
    return data.refCnt();
  }

  @Override
  public ByteBufHolder retain() {
    data.retain();
    return this;
  }

  @Override
  public ByteBufHolder retain(int increment) {
    data.retain(increment);
    return this;
  }

  @Override
  public ByteBufHolder touch() {
    data.touch();
    return this;
  }

  @Override
  public ByteBufHolder touch(Object hint) {
    data.touch(hint);
    return this;
  }

  @Override
  public boolean release() {
    return data.release();
  }

  @Override
  public boolean release(int decrement) {
    return data.release(decrement);
  }

  /**
   * Return {@link ByteBuf#toString()} without checking the reference count first. This is useful to
   * implement {@link #toString()}.
   */
  protected final String contentToString() {
    return data.toString();
  }

  @Override
  public String toString() {
    return StringUtil.simpleClassName(this) + '(' + contentToString() + ')';
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o instanceof ByteBufHolder) {
      return data.equals(((ByteBufHolder) o).content());
    }
    return false;
  }

  @Override
  public int hashCode() {
    return data.hashCode();
  }
}
